Synthesis of halogenated alkoxyethane

Abstract

A process for continuous preparation of halogenated alkoxyethane of general formula XClHC—CF 2 OR, where X is —Cl or —F and OR is C 1-4 alkoxy, the process comprising a step of introducing in a plate reactor reaction components comprising (i) a compound of general formula XClC═CF 2 , (ii) a base, and (iii) a C 1-4 alkanol, wherein a) the plate reactor comprises a fluidic module defining one or more fluidic path(s) through which the reaction components flow as a reaction mixture, and b) the halogenated alkoxyethane is formed at least upon the reaction components mixing, with the so formed halogenated alkoxyethane flowing out of the plate reactor in a reactor effluent.

The claims defining the invention are as follows: 
     
         1 . A process for continuous preparation of halogenated alkoxyethane of general formula XClHC—CF 2 OR, where X is —Cl or —F and OR is C 1-4  alkoxy, the process comprising a step of introducing in a plate reactor reaction components comprising (i) a compound of general formula XClC═CF 2 , (ii) a base, and (iii) a C 1-4  alkanol, wherein
 i. the plate reactor comprises a fluidic module defining one or more fluidic path(s) through which the reaction components flow as a reaction mixture, and 
 ii. the halogenated alkoxyethane is formed at least upon the reaction components mixing, with the so formed halogenated alkoxyethane flowing out of the plate reactor in a reactor effluent. 
 
     
     
         2 . The process of  claim 1 , wherein the plate reactor comprises a stack of fluidic modules defining the one or more fluidic path(s) through which the reaction components flow as a reaction mixture. 
     
     
         3 . The process of  claim 1 or 2 , wherein the fluidic module(s) is/are at a temperature of from about −15° C. to about 45° C. 
     
     
         4 . The process of any one of  claims 1-3 , wherein the one or more fluidic path(s) provide a total internal volume of at least 10 ml. 
     
     
         5 . The process of any one of  claims 1-4 , wherein the reactor effluent contains at least 90% by volume of the halogenated alkoxyethane. 
     
     
         6 . The process of any one of  claims 1-5 , wherein the plate reactor provides a residence time of less than about 5 minutes. 
     
     
         7 . The process of any one of  claims 1-6 , wherein the reaction mixture is obtained by mixing (i) a solution of the C 1-4  alkanol and the base with (ii) the compound of general formula XClC═CF 2 . 
     
     
         8 . The process of any one of  claims 1-7 , wherein the mixing is performed upstream of the one or more fluidic path(s). 
     
     
         9 . The process of any one of  claims 1-8 , wherein the mixing is performed by combining (i) a flow of the solution of the C 1-4  alkanol and the base with (ii) a flow of the compound of general formula XClC═CF 2  according to a flow-rate ratio from 1:1 to 10:1. 
     
     
         10 . The process of any one of  claims 1-9 , wherein the base is used in an amount of between 1% and 30% by weight relative to the total weight of base and C 1-4  alkanol. 
     
     
         11 . The process of any one of  claims 1-10 , wherein the compound of general formula XClC═CF 2  is Cl 2 C═CF 2  or FClC═CF 2 . 
     
     
         12 . The process of any one of  claims 1-11 , wherein the C 1-4  alkanol is selected from methanol (CH 3 OH), ethanol (CH 3 CH 2 OH), 1-propanol (CH 3 CH 2 CH 2 OH), 2-propanol ((CH 3 ) 2 CHOH), 1-butanol (CH 3 CH 2 CH 2 CH 2 OH), 2-butanol (CH 3 CH 2 CHOHCH 3 ), 2-methyl-1-propanol ((CH 3 ) 2 CHCH 2 OH), 2-methyl-2-propanol ((CH 3 ) 3 COH), and a combination thereof. 
     
     
         13 . The process of any one of  claims 1-12 , wherein the halogenated alkoxyethane is Cl 2 HC—CF 2 OCH 3  (methoxyflurane) or ClFHC—CF 2 OCH 3 . 
     
     
         14 . The process of any one of  claims 1-13 , wherein the base comprises an alkali metal base cation or an ammonium base cation. 
     
     
         15 . The process of any one of  claims 1-14 , wherein the base is selected from sodium hydroxide, potassium hydroxide, sodium methoxide, potassium methoxide, tetrabutylammonium hydroxide, benzyl(trimethyl)ammonium hydroxide, N-methyl-N,N,N-trioctylammonium chloride, tetraethylammonium hydroxide, tetramethylammonium hydroxide, and tetramethylphosphonium hydroxide. 
     
     
         16 . The process of any one of  claims 1-15 , further comprising a purification procedure that comprises the steps of:
 a) adding one of an amine and an acid to the reactor effluent or an organic phase separated from the reactor effluent,   b) adding a polar liquid to the mixture obtained in step a) to induce phase separation and formation of a polar phase and a separate organic phase, the organic phase containing the halogenated alkoxyethane,   c) adding the other of the amine and the acid not used in step a) to the organic phase obtained in step b) to thereby purify the halogenated alkoxyethane.   
     
     
         17 . The process of  claim 16 , further comprising a step d) of isolating the purified halogenated alkoxyethane. 
     
     
         18 . The process of  claim 16 or 17 , wherein the amine is selected from ethylenediamine (1,2-diamnoethane), 1,3-diaminopropane, diethylenetriamine, di-n-propylamine, n-butylamine, ethanolamine, pyrrolidine, 2-aminobutane, and a mixture thereof. 
     
     
         19 . The process of any one of  claims 16-18 , wherein the acid is selected from hydrochloric acid, sulfuric acid, sulphurous acid, methanesulfonic acid, trifluoromethanesulfonic acid, phosphoric acid, acetic acid, trifluoroacetic acid, nitric acid, nitrous acid, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, and a combination thereof. 
     
     
         20 . The process of any one of  claims 16-19 , wherein the purified halogenated alkoxyethane is isolated by fractional distillation. 
     
     
         21 . The process of any one of  claims 16-20 , wherein the polar liquid is water. 
     
     
         22 . The process of any one of  claims 16-21 , the process being for purifying the halogenated alkoxyethane from impurities comprising one or more of methoxyethene (ME), orthoesters (OE), and methyl dichloroacetate (MDA). 
     
     
         23 . Halogenated alkoxyethane of general formula XClHC—CF 2 OR, where X is —Cl or —F and OR is C 1-4  alkoxy, obtained in accordance with the process of any one of  claims 16-22 , the halogenated alkoxyethane having purity of at least 99%.